This invention relates to an intake air preheater for a diesel engine, particularly to an intake air preheater for a diesel engine with a heat storage exchanger and a built-up heating body, which facilitates the diesel engine to start at low temperature.
Chinese Utility Model 93212913.7 disclosed a conventional intake air preheater for a diesel engine. FIG. 1 shows a sectional view of the conventional intake air preheater. The reference numerals in FIG. 1 represent the following elements:
1xe2x80x94a heating chamber;
2xe2x80x94an exchanger fixing bolt;
3xe2x80x94an outer housing;
4xe2x80x94a first stage sensitive to heat ceramics heater;
5xe2x80x94a first stage heat exchange plate;
6xe2x80x94a central baffle plate;
7xe2x80x94a second stage sensitive to heat ceramics heater,
8xe2x80x94a second stage heat exchange plate;
9xe2x80x94an adiabatic ring;
10xe2x80x94a heating chamber;
11xe2x80x94a heat conducting bar;
12xe2x80x94a sensor terminal;
13xe2x80x94a power supply terminal; and
14xe2x80x94a temperature sensor
The preheater is installed between an air filter and an intake air manifold of a diesel engine. There is provided in a preheater twelve heat conducting bars evenly spaced from each other along the periphery of the preheater.
When the power supply is turned on, the first and second stage sensitive to heat ceramics heaters 4,7 generate heat to a rated temperature and transmit heat to the first and second stage heat exchange plates 5, 8. When the first and second stage heat exchange plates 5, 8 are heated to the rated temperature, a controller gives off a sound and/or light signal after receiving the signal from the temperature sensor 14. The sound and/or light signal means that the diesel engine may start.
The heating process is as follows. The air enters the heat chamber 1 from the air filter. The air then flows through and is heated by the first stage sensitive to heat ceramics heater 4 under the guidance of the adiabatic ring 9 and the central baffle plate 6. Next, the hot air is further heated by the second stage sensitive to heat ceramics heater 7 and flows into the heating chamber 10. Finally, the heated air flows into the diesel engine from heating chamber 10. The test shows that a diesel engine may start at a low temperature to xe2x88x9230xc2x0 C. by means of such a preheater.
However, such conventional preheater has the following disadvantages:
1) Because the diesel engine starts as soon as the air in the preheater is heated to the rated temperature, a smaller amount of heat is initially generated, the temperature in the preheater is low and the sustaining-heating ability is poor.
2) The preheater is unable to store heat because of its light weight. The efficiency of heat exchange is also low because the heat exchange plate is provided with small surface area.
3) Although the baffle plate between the heating chamber 1 and heating chamber 10 facilitates to heat the air in the two chambers during the preheating, it will unfavorably prevent the air from entering the diesel engine in the normal operating state, thereby reducing the efficiency of the diesel engine and increasing oil consumption.
An object of this invention is to provide an intake air preheater for a diesel engine which overcomes the problems described above in the prior art.
In accordance with the present invention, there is provided an intake air preheater for a diesel engine comprising an outer housing comprising a first housing with an air discharge port and a second housing with an air intake port; a preheater body comprising at least two built-up heating bodies and at least three heat storage exchangers, a straight air passage formed in the preheater body, the preheater body installed in the outer housing so that a surrounding air passage is formed between the outer housing and the preheater body; wherein a valve plate is pivotably provided in the straight air passage to open or close the straight air passage.